The present invention relates to an electric power trading support system to be used by electric power retailers (recently appearing since the deregulation or liberalization of the electric power industry) when the electric power retailer sells or supplies electric power generated by its own private electric generator to customers (customers demanding electric power) together with electric power (backup electric power) purchased from other suppliers (electric power company, electric power exchange/market, other electric power retailers, etc.), and in particular, to an electric power trading support system for letting the electric power retailer estimate and predict the demand of the electric power and evaluate, examine and optimize the planning of the ratio between the private power generation and the power purchase (backup power) or the quantities of them in order to increase the profit.
Until recently, electric power was generated by electric power companies only. In order to let the electric power companies plan operation schedules of power generators on the next day, various techniques for predicting electric power demand on the next day have been developed, in which prediction techniques employing a neural network, multiple linear regression analysis, etc. are well known.
Since electric power companies were the only provider of the electric power, fluctuation of the electric power demand on the day of power generation used to be taken care of by each electric power company, by adjusting the output level of its own power generators. In a method disclosed in JP-A-2002-84661 (hereinafter referred to as “patent document #1”), the amount of electric power to be generated by each power generator (or to be covered by each power purchase contract) for supplying sufficient electric power to the customers is determined starting from a power generator (or power purchase contract) of the lowest cost, under several conditions such as whether the demand/supply of each power generator (or the power purchase contract) can be adjusted on the day, minimum power generating capacity (or minimum power purchase quantity), etc.
In a method disclosed in JP-A-2001-327074 (hereinafter referred to as “patent document #2”), an electric power retailer gathers information on the demand of each customer by use of a network, predicts the electric power demand of the next day, and presents the result of the electric power demand prediction of the next day to each customer. Each customer is allowed to declare the amount of electric power to be used on the next day easily and precisely based on the electric power demand prediction result presented by the electric power retailer. In a method disclosed in JP-A-2002-315191 (hereinafter referred to as “patent document #3”), each customer is commissioned to predict its own electric power demand, and the electricity charges are changed depending on the accuracy of the prediction made by the customer.
Meanwhile, more and more electric power retailers are appearing in recent years since the deregulation of the electric power industry. The electric power retailer generates electric power by its own private power generator and supplies the generated electric power. If the electric power retailer owns a private power generator having a power generating capacity adapted to peak electric power demand, operating ratio of the private power generator remains low and the profits to the electric power retailer declines. Therefore, in peak hours, the electric power retailer purchases backup electric power (hereinafter, also referred to as “backup power”) from an electric power company, an electric power exchange, another electric power retailer, an owner of a private power generator having surplus power, etc. Since storage of electric power is generally impossible and it is also difficult to rapidly increase/decrease (especially, rapidly increase) the amount of power generation, the electric power retailer who purchases the backup power has to previously report or declare expected quantities of hourly power purchase (demand) to the supplier of the backup power (electric power company, electric power exchange, another electric power retailer, etc.) prior to the day of power supply. However, if the actual demand deviates from the prediction (the prediction is off) and the electric power retailer uses too much backup power exceeding a threshold value (3% of the contract demand, for example), the electric power retailer has to pay an expensive penalty to the backup power supplier.
On the other hand, even if the quantity of backup power actually used is smaller than the declared power purchase quantity, the electric power retailer has to pay for the declared quantity. The power purchase contract includes such severe conditions that are characteristic of electric power.
The deviation of the actual demand from the prediction is inevitable. Paying the penalty to the backup power supplier can be avoided by estimating the demand a little higher and reporting a little larger power purchase quantity to the backup power supplier, or by setting the ratio of the private power generation at a low level so as to give a safety margin to the private power generator and let the power generator cope with the fluctuation of demand. However, in either case, a lot of the expensive backup power has to be purchased without making effective use of the private power generator which can generate electric power at a low unit cost. Therefore, profitability is necessitated to be deteriorated unless the ratio between the private power generation and the power purchase is set properly.
As described above, reduction of the cost for receiving the supply of the backup power is a critical issue for the electric power retailers.